Figure 1. Validated IFNγ ELISpot assay discriminates between SARS-CoV-2 naïve and convalescent T-cell responses.
A. SARS-CoV-2 spike and nucleocapsid protein domains with corresponding peptide pools. B. Schematic of IFNγ ELISpot assays. C. Representative ELISpot wells from a healthy control (M002) and a SARS-CoV-2-convalescent donor (C22) with the number of spot forming units (SFU) per 2.5×105 PBMC quantified (number next to well). D. SFU are shown for each subject in the SARS-CoV-2 convalescent (n=25) or healthy control (n=19) groups. Bars represent mean ± standard error of the mean. E. Composite ELISpot results from D. Lines represent median ± 95% confidence intervals. Dotted line indicates the positive threshold of 6 SFU per 2.5×105 PBMC.